JP2993591B2 - Adhesive for vinylidene fluoride resin - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluororesin adhesive which is effective for producing a laminate having a vinylidene fluoride resin film having weather resistance, stain resistance, chemical resistance and the like on its surface. The laminate is in the form of a film, sheet, cloth composite, etc.
Used for interior and exterior materials, tents and membrane roofing materials.

[0002]

2. Description of the Related Art Polyvinylidene fluoride (hereinafter "PVD")
F ". ) Or vinylidene fluoride copolymer (hereinafter, these are collectively referred to as “VDF resin”).
Stable against highly corrosive chemicals and ultraviolet rays,
Furthermore, it is widely known that it has excellent mechanical properties, and it has excellent melt processing properties such as extrusion molding and powder coating, especially among fluororesins. Many are used. Further PVD
F has excellent gas barrier properties among fluororesins,
Applications utilizing this property are also being considered.

[0003] Conventionally, attempts have been made to attach a VDF resin film to another material to impart chemical resistance, stain resistance, etc. to the surface.
A product in which a thick film is bonded to a soft vinyl chloride tent film material through an acrylic adhesive is used for truck hoods and the like. Further, among the VDF resins, those having flexibility are disclosed in
-206615 No.
It is called "soft fluororesin". ) Is disclosed in JP-A-64-22.
As described in Japanese Patent No. 547, a method of bonding a thin film of a soft fluororesin to various substrates via a polyurethane adhesive is known, and is used for tablecloths, wall coverings, curtains and the like.

[0004]

SUMMARY OF THE INVENTION A conventionally known VD
Adhesives between F-based resin and other materials that are practically used are all inferior to VDF-based resin in terms of weather resistance, water resistance, heat resistance, etc. of the adhesive itself, and can be used outdoors for a long time. When used under severe conditions such as temperature and humidity, the adhesive deteriorates and the laminate is peeled off.

[0005] Accordingly, the present invention provides a composite of a VDF resin base material and a base material made of another material, which has a high adhesive strength and excellent durability such as weather resistance, water resistance and heat resistance. It is intended to provide an agent.

[0006]

Means for Solving the Problems The present inventors have conducted intensive studies on a method of bonding a VDF-based resin base material to a base material made of another material, and as a result, disclosed in JP-A-58-206615.
The adhesive comprising the organic solvent solution of the soft fluororesin and the polyisocyanate obtained has good durability of the adhesive itself and good adhesive strength between the respective layers, and has found that the above-mentioned problems can be solved.

The VDF resin to be used in the present invention is polyvinylidene fluoride or a copolymer of vinylidene fluoride and another monomer, and the molar ratio of the vinylidene fluoride structural unit to the structural unit based on the other monomer is 100/0. From 50
/ 50 range. Copolymers containing more than 50% of the structural units based on other monomers generally become very rubbery polymers and are not suitable for the purpose of modifying the surface properties of the substrate. The other monomer copolymerized with VDF is not particularly limited, and examples thereof include tetrafluoroethylene, hexafluoropropylene, chlorotrifluoroethylene, and hexafluoroacetone.
Resins containing copolymers of polyvinylidene fluoride, vinylidene fluoride and other monomers or copolymers of different types of vinylidene fluoride and other monomers in the form of a block polymer or a graft polymer, and also a blend resin thereof. It is included in the VDF resin targeted in the present invention.

[0008] The soft fluororesin used in the adhesive of the present invention comprises at least one kind of monomer containing at least one kind of fluorine-containing monomer, and a monomer having a double bond and a peroxy bond in the molecule simultaneously. To obtain a fluorocopolymer having a peroxy bond in its molecule and having a glass transition temperature of room temperature or lower as the first step, and in the second step, obtaining the fluorinated copolymer in the first step. A resin obtained by graft copolymerization of a vinylidene fluoride monomer in an aqueous emulsion or dispersion solvent of the obtained copolymer. This resin has the property that the copolymer part whose glass transition temperature is below room temperature has the flexibility and solubility necessary for adhesives and the compatibility with other base materials, and the compatibility with other base materials. It is considered that the PVDF portion generated by graft copolymerization exhibits heat-fusibility with the VDF-based resin.

Examples of the monomer having a double bond and a peroxy bond in the molecule used herein include unsaturated peroxyesters such as t-butylperoxymethacrylate and t-butylperoxycrotonate, and t-butylperoxycrotonate. Examples thereof include unsaturated peroxycarbonates such as allyl carbonate and p-menthane peroxyallyl carbonate.

The composition of the fluorine-containing copolymer having a glass transition temperature of room temperature or lower is a binary copolymer of vinylidene fluoride (VDF) and hexafluoropropene (HFP), a copolymer of VDF, HFP and tetrafluoroethylene. Examples include a terpolymer of ethylene (TFE) and a terpolymer of VDF and chlorotrifluoroethylene (CTFE), but the composition is not particularly limited.

The weight ratio of the fluorine-containing copolymer produced in the first step whose glass transition temperature is below room temperature to the PVDF graft-copolymerized in the second step is 95/5 to 30 /.
It is desirably in the range of 70. Below this range, V
The thermal adhesiveness to the DF resin is insufficient, and if it exceeds this range, the flexibility required for the adhesive and the solubility in organic solvents are insufficient.

Various kinds of polyisocyanates to be mixed with the soft fluororesin in the present invention can be used. The mixing of the polyisocyanate improves the adhesion with other base materials, and reacts mainly with the terminal portion of the soft fluororesin,
It is considered that the adhesive layer has an effect of improving the creep resistance, heat resistance, and the like of the adhesive layer.

The mixing ratio of the polyisocyanate is preferably in the range of 0.3 to 50 parts by weight, more preferably 0.5 to 30 parts by weight, per 100 parts by weight of the soft fluororesin. If the amount is less than 0.3 parts by weight, the effect of adding the polyisocyanate is not sufficiently exhibited. If the amount is more than 50 parts by weight, the flexibility of the adhesive layer is lost and the chemical resistance, weather resistance and the like are undesirably reduced.

The polyisocyanate in the adhesive of the present invention is not particularly limited.
Tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), dodecamethylene diisocyanate, 1,6,11-undecane triisocyanate,
2,2,4-trimethylhexane diisocyanate,
2,6-diisocyanatomethyl caproate (LD
I), bis (2-isocyanatoethyl) fumarate,
Bis (2-isocyanatoethyl) carbonate, 2-
Isocyanate ethyl-2,6-diisocyanate hexanoate, isophorone diisocyanate (IPD
I), 4,4'-diphenylmethane diisocyanate (MDI), dicyclohexylmethane diisocyanate (hydrogenated MDI), cyclohexylene diisocyanate,
Methylcyclohexylene diisocyanate (hydrogenated TD
I), bis (2-isocyanatoethyl) -4-cyclohexene-1,2-dicarboxylate, xylylene diisocyanate (XD1), diethylbenzene diisocyanate, toluene diisocyanate (TDI), and urethane adducts and burettes prepared therefrom Bodies, isocyanurates, blocked isocyanates, urethane prepolymers and the like, for example, water-modified products of HDI,
Examples include TDI dimer, TDI trimethylolpropane adduct (L), HMDI-biuret, L-phenol block, IPDI trimer and the like, and a crude product thereof or a mixture of two or more thereof.

In the adhesive of the present invention, the above polyisocyanate may be selected and used. However, in general, discoloration is not preferred, so that an isocyanate group called non-yellowing type or hardly yellowing type is adjacent to the benzene nucleus. Not done, for example, aliphatic diisocyanates such as HDI, XDI, LDI or IPDI, hydrogenated MDI, hydrogenated XDI
And alicyclic isocyanates such as urethane adducts, burettes, isocyanurates, blocked isocyanates, and urethane prepolymers prepared from these polyisocyanates.

Another substrate which is an object of the present invention includes an active hydrogen (H) capable of reacting with an isocyanate group on its surface.
X) is desirable because it does not require any special pretreatment. The functional group containing such active hydrogen -OH, -COOH, -NH _2, -CONH
-, An ester group and the like. Examples of the polymer containing these in the structure include poly (meth) acrylic acid (ester), polyurethane and polyamide. Also, even if the main chain in the structure does not contain active hydrogen, if the structure has a functional group containing active hydrogen at the end of the structure, or if a substance containing active hydrogen is blended, then even if the surface has active hydrogen, In the case of coating with a substance containing, for example, the adhesive of the present invention is used.

When the substrate is metal, glass, etc., various plastics
Immers, for example, means for applying a silane coupling agent
Is taken. Silane coupling agent used in the present invention
Is R ¹-Si (OR^Two)_ThreeA silane represented by the formula:¹
Is an organic functional group such as a vinyl group or an amino group, R^TwoIs water
Decomposable groups such as halides, acyloxy groups,
It is a coxy group. These silanes are, for example,
Lopropylmethyldichlorosilane, γ-chloropropyl
Methyldimethoxysilane, γ-chloropropylmethyldi
Ethoxysilane, γ-chloropropyltrimethoxysila
And chromium such as γ-chloropropyltriethoxysilane.
Low alkyl group-containing silane, vinyltrichlorosilane,
Nyltriethoxysilane, vinyl tris (methoxyeth
Xy) silane, γ-methacryloxypropyl trimethoxy
Unsaturated group-containing silanes such as silane, γ-glycidoxy
Propyltrimethoxysilane, γ-glycidoxypropyl
Rutriethoxysilane, γ-glycidoxypropylmethyl
Ludiethoxysilane, γ-glycidoxypropyl methoxy
Sisilane, γ-glycidoxypropylsilanetriol
Epoxy group-containing sila having a γ-glycidoxy group such as
, Γ-mercaptopropyltrimethoxysilane
Mercapto group-containing silane, γ-aminopropyl trimeth
Xysilane, γ-aminopropyltriethoxysilane,
γ-aminopropylmethyldiethoxysilane, N- (2
-Aminoethyl) -3-aminopropyltrimethoxy
Amino group-containing silanes such as orchids are mentioned,
Mino group containing silanes are most preferred.

For resins such as polyethylene and polytetrafluoroethylene, which are considered to be difficult to bond, a functional group having active hydrogen is generated on the surface by means of flame treatment, corona discharge treatment, sodium etching or the like. Are also known, and these are also applicable to the adhesive of the present invention.

Accordingly, the material of the base material is not particularly limited as long as it can form fibers or plate-like bodies. Therefore, the material of the base material depends on the required properties such as mechanical strength, heat resistance, weather resistance and light transmission. You can select various things.

The shape of the substrate using the adhesive of the present invention is not particularly limited, but it is preferable that the appearance is a plate-like body. In particular, it is preferable that at least one of the two substrates sandwiching the adhesive layer has a plate shape, a sheet shape, and a film shape. These substrates may be non-porous, perforated, woven, non-woven or patterned.

Various organic solvents can be used as the organic solvent constituting the adhesive of the present invention. However, in view of the solubility of the soft fluororesin, highly polar solvents such as N, N-dimethylformamide, N, N- Dimethylacetamide, N-methylpyrrolidone, and ketones and esters such as acetone, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, and tetrahydrofuran are preferred.
These organic solvents can be used as a mixture, but in this case, it is preferable to use the above-mentioned highly polar solvent in combination.

The mixing ratio of the organic solvent is determined in consideration of the viscosity required for the desired adhesion. Usually, the total amount of the soft fluororesin and polyisocyanate in 100 parts by weight of the adhesive solution is 1 to 60. Adjusted to be by weight.

The adhesive of the present invention is usually applied to the base material having active hydrogen, by volatilizing the solvent, and then thermally bonding to the VDF resin. The coating method may be an ordinary method, for example, dipping, brush coating, spray coating, roll coating, curtain coating, flow coating, etc., and the evaporation of the solvent may be performed with or without heating. The heat bonding is performed by heating under pressure or non-pressurized state, and the temperature is limited by the material of the base material. It is preferable to perform the following. If the temperature is 180 ° C. or lower, the VDF resin does not melt and is not adhered, which is not preferable. Load pressure is not essential, but 5-10
It is preferable to apply a pressure of about 0 kgf / cm ² because smoothness can be obtained.

As the method of heat bonding, any of a single-wafer method and a continuous method using a roll can be adopted.

[0025]

The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

Example 1 (A) Production of Soft Fluororesin Pure water was placed in a 100 L stainless steel autoclave.
Kg, 100 g of potassium persulfate, 150 g of ammonium perfluorooctanoate and 100 g of t-butylperoxyallyl carbonate were added, and after evacuation, 12.5 kg of vinylidene fluoride monomer (VDF) and 7.55 kg of chlorotrifluoroethylene monomer (CTFE) were charged. The polymerization reaction was carried out at a temperature of 50 ° C. for 20 hours while stirring. The product was obtained in the form of a white latex, which was salted out to obtain rubber-like particles. After washing with water and vacuum drying,
It was washed with n-hexane to remove unreacted t-butylperoxyallyl carbonate, and dried again under vacuum to obtain 16 kg of a white powder copolymer. The DSC curve of this copolymer showed an exothermic peak due to decomposition of the peroxy group of 160-18.
The copolymer had an active oxygen content of 0.042% by iodometric titration. The glass transition temperature of this copolymer was measured at -26.5 ° C. by DSC, and the molar ratio of units based on VDF and CTFE in the copolymer by elemental analysis was 80/20.

In the next step, the white powder copolymer 12
Kg and 75 kg of Freon R-113 were charged in a 100 L stainless steel autoclave, and after evacuation, 6 kg of vinylidene fluoride monomer was charged and polymerization was carried out at 95 ° C. for 24 hours. The resulting polymer was separated from the solvent and then dried to obtain 16.6 kg of a soft fluororesin as a white powder. Calculated from the yield, this soft fluororesin was obtained by graft copolymerizing 38.3 parts by weight of vinylidene fluoride monomer with respect to 100 parts by weight of the copolymer obtained in the first step. (B) Production of Adhesive 100 g of the soft fluororesin produced in the above (A) and 400 g of N, N-dimethylformamide as a solvent were put into a 1 L glass beaker, and a high-speed stirrer (T .K homodisper) to give 2,000
The mixture was stirred at 0 rotation for 1 hour to dissolve the resin. To this solution was further added 70 g of methyl ethyl ketone and Coronate HX (HDI
Is a non-yellowing type polyisocyanate having an isocyanurate ring. 1) g was added with stirring to prepare an adhesive. (C) Adhesion of nylon cloth / VDF resin 30 cm square nylon 6 fiber taffeta cloth (720
d, 0.3 mm thickness), the adhesive prepared in the above (A) was applied to one side with a bar coater, and dried in an oven at 130 ° C. for 2 minutes. The amount of adhesive resin applied to the cloth is about 15 g /
It was m ^2.

Next, as a VDF resin, PVDF (AUSI
The mixed resin of 1: 2 (weight ratio) of the soft fluororesin used in (A) and (HYLAR461 manufactured by MONT) was kneaded by a two-roll molding machine heated to 180 ° C., and then pulled out at a constant speed. A 1 mm film was produced.

The nylon cloth coated with the adhesive and the VDF-based resin film are stacked and sandwiched between two 1 mm-thick stainless steel plates, and pressed at 10 kgf / cm ² in a compression molding machine heated to 200 ° C. After holding for 2 minutes, it was taken out and allowed to cool to produce a laminate. (D) Measurement of adhesive peel strength The adhesive peel strength of the laminate manufactured in (C) was measured according to JIS.
It measured according to the tensile peeling test method prescribed | regulated to K6328 (rubber cloth). Table 1 shows the measured values and fracture sites. (E) Moisture / heat resistance evaluation The laminate produced in the above (C) was put in a constant temperature / humidity bath adjusted to 85 ° C. and 95% humidity, and was taken out after 7 days had passed.
The adhesive strength of (D) was measured. Table 1 shows the results
It can be seen that the adhesive has good wet heat resistance.

[0030]

[Table 1]

Comparative Example 1 A polyurethane-based adhesive (Chrisbon, manufactured by Dainippon Ink Co., Ltd., main agent: 100 parts by weight of Crisbon C-4365T, cross-linking agent: 8 parts by weight of Crisbon NX) Parts, accelerator: 3 parts by weight of Chrisbon Accel HM, solvent (DMF / toluene = 1 /
140 parts by weight)) with a bar coater,
The solvent was evaporated by drying in an oven for 1 minute. The solid content of the adhesive was about 40 g / m ² .

This film was immediately bonded to the nylon cloth used in Example 1 and aged at room temperature for 24 hours. The peel strength of the laminate was measured at the initial stage and after the wet heat resistance test in the same manner as in Example 1. The results are shown in Table 1. It can be seen that the adhesive has clearly inferior wet heat resistance as compared with Example 1.

Example 2 A glass plate having a size of 20 cm square and a thickness of 3 mm was immersed in a 5% aqueous solution of a silane coupling agent (Aminosilane SH6020 manufactured by Dow Corning Toray Silicone Co., Ltd.). Dried for minutes. The adhesive prepared in Example 1 (B) was applied to one surface of the glass plate with a bar coater, and dried in an oven at 130 ° C. for 2 minutes. The amount of resin adhered after the solvent was evaporated was about 10 g / m ² .

A commercially available 0.15 mm-thick PVDF film (manufactured by SOLVEY) was placed between two fluororubber plates according to the adhesive-coated surface of this glass plate, and 200 g of the film was sandwiched.
At a pressure of 5 kgf / cm ² in a compression molding machine heated to 2 ° C.
After holding for a minute, it was taken out and cooled to produce a laminate.
The adhesive strength of this laminate was measured in the same manner as in Example 1. Further, this laminated body is connected to a sunshine weatherometer (S
(WM: black panel temperature: 60 ° C.), the VDF-based resin film was exposed to light so as to be exposed to light, taken out after 1000 hours, and the change in peeling strength before and after the exposure and the change in appearance were measured. The results are shown in Table 2, and it is clear that the adhesive of the present invention has excellent weather resistance.

[0035]

[Table 2]

Comparative Example 2 A soft fluororesin solution in which no polyisocyanate was mixed during the production of the adhesive of Example 1 (B) was prepared, and a glass plate was prepared in the same manner as in Example 2 except that this solution was used as an adhesive. A laminate of the PVDF film was manufactured, and the peel strength was measured. The results are shown in Table 2, and the adhesive strength is clearly inferior to Example 2.

Comparative Example 3 NB manufactured by Kyodo Yakuhin Co., Ltd. was applied to the glass plate prepared in Example 2 and treated with a silane coupling agent as an acrylic adhesive.
After coating -91B with a bar coater, it was dried at a temperature of 80 ° C for 2 minutes. The amount of resin adhered after the solvent was evaporated was about 10 g / m ² . The glass plate and the PVDF film were thermally bonded in the same manner as in Example 2 to produce a laminate, and the peel strength and appearance change before and after exposure to a sunshine weatherometer (under the same conditions as in Example 2) for 2,000 hours were measured. It was measured. The results are shown in Table 2. As compared with Example 2, the weather resistance of the adhesive was clearly inferior.

Reference Example A laminate of a glass plate and a PVDF film was manufactured in the same manner as in Example 2 except that the glass plate was not treated with a silane coupling agent, and the peel strength was measured. The results are shown in Table 2. The adhesive strength was clearly inferior to that of Example 2, but this was because strong bonds were not formed because there was no active hydrogen on the surface of the adherend. It is estimated to be.

[0039]

As described in Examples, the adhesive of the present invention is effective for bonding a VDF resin substrate to a substrate having active hydrogen on its surface and has excellent durability. When a laminate is formed using the adhesive of the present invention, the adhesive is applied to the side of the substrate having active hydrogen, and after the solvent is volatilized, the adhesive is thermally bonded to the VDF resin. The adhesive surface after volatilization does not remain sticky, and the adhesive-treated substrate can be stored in a roll form, which is extremely advantageous for continuous production of adhesive products and mass production. This has the effect.

──────────────────────────────────────────────────の Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) C09J 1/00-201/10 C08F 259/08 CA (STN) REGISTRY (STN)

Claims (6)

(57) [Claims] 1. An adhesive used for a substrate comprising a vinylidene fluoride resin, comprising a soft fluororesin, a polyisocyanate, and an organic solvent, wherein the soft fluororesin comprises at least one kind of fluorine-containing monomer. One or more monomers including a monomer having both a double bond and a peroxy bond in the molecule are copolymerized to contain a peroxy bond in the molecule, and the glass transition temperature is below room temperature. The first step is to produce a fluorinated copolymer. In the second step, a vinylidene fluoride monomer is graft-copolymerized in an aqueous emulsion or dispersion solvent of the copolymer obtained in the first step. An adhesive that is a stiffened resin. 2. The vinylidene fluoride resin is polyvinylidene fluoride or a copolymer of vinylidene fluoride and another monomer, wherein the molar ratio of the vinylidene fluoride structural unit to the structural unit based on the other monomer is 100/0 to 50. 2. The adhesive according to claim 1, wherein the ratio is in the range of / 50. 3. An adhesive constituting an adhesive layer interposed between two bases, wherein one base is made of a vinylidene fluoride resin and the other base is made of a material having active hydrogen on its surface. The adhesive according to claim 1, wherein the adhesive comprises: 4. The adhesive according to claim 1, wherein the organic solvent is N, N-dimethylformamide. 5. The adhesive according to claim 1, wherein the polyisocyanate is hexamethylene diisocyanate or an isocyanurate derived therefrom. 6. The surface of the other substrate is treated with a primer.
4. The adhesive according to claim 3, wherein the adhesive is a treated substrate.